Method of tempering leather soles



June 25, 1935. w. c. WRIGHT 2,005,765

METHOD OF TEMPERING LEATHER SOLES Filed March 29, 1933 44 3 14 15 {0 I 1 1!? 1a 2 u 10 40 25' 45 52 24 36 as I, a? 8:3 2 3030; I n u 00 0 Tzrvewfior Patented June 25, 1935' UNITED STATES PATENT OFFICE American Shoe Machinery Corporation,

Boston, Mass, a corporation of Massachusetts Application March 29, 1933, Serial No. 663,368

2 Claims.

My present invention is a novel and improved method of tempering leather, particularly sole leather, whether sides, hides, blocks, blanks, or shoe soles, and is a continuation in part, of my prior application on pressure tempering machines, Ser. No. 529,705, filed April 13, 1931.

The proper tempering of leather soles, whether insoles or outsoles, has heretofore been the main factor in holding up and delaying the manufacture of boots and shoes. It is essential, for many reasons, that leather soles should be properly tempered before they are incorporated in a boot or shoe. Leather is a constant variable, and is received by the shoe factories, either in pieces or as cut soles, in varying conditions. Some soles will be hard, some will be soft and some will have hard spots and soft spots in them. These varying conditions and qualities are inherent in the leather, and make theftrimming, channeling, sewing, bottom-laying molding and other operations ex'ceedingly diflicult. The primary pur pose of tempering leather or soles, therefore, is

to make the soles or leather uniform in condition, flexibility, and pliability, and to make said soles easier to work, channel, trim, and sew.

In mysaid prior and copending application I have disclosed and claimed broadly a suitable machine for use in carrying out my present process, and in this present application I have elected-to claim broadly my improved process or method of pressure tempering disclosed and described in said prior application.

Also, in the present application I have illustrated an extremely simple pressure tempering structure which can be utilized to carry out my process, as well as the more complex and automatic machine of said prior application, or the machines of the applications of Messrs. Fickett, Forman, and Arthur, illustrating other developments of pressure tempering machines to carry out my present method, said applications being Ser. Nos. 661,264, filed Mar. 1'1, 1933, and 673,804, filed June 1, 1933.

In the handling of leather of various kinds and for almost any purpose, particularly where the leather is fabricated into articles such as boots and shoes, leather bags, cases, interwoven belts, structures, or the like where the leather must be flexed and bent in manufacture, and particularly also where relatively heavy sole leather is being worked, it is important and necessary to have such leather in temper.

Various methods have been devised for tempering leather, as by bending and flexing, soaking in water or tempering solution, heating the water,

putting the same under increased air pressure, or the like, but none of these prior methods have been fully satisfactory.

In my various developments of tempering methods and processes for treating sole leather, I have discovered that much quicker, better, more efficient, and more uniform tempering is secured by subjecting the leather to a positive hydraulic .pressure capable of a quick and relatively heavy degree of pressure.

For this purpose I enclose the leather to be treated, whether a large section, a block of leather, or a leather sole, a plurality of soles or pieces, in a pressure-tight receptacle, preferably partially, or substantially full, of the liquid tempering solution, or water; apply the pressure-tight cover, and then supply additional liquid under pressure, permitting the air which may be contained within, when the cover is applied, to escape and continuing the liquid supply until any desired pressure, to which the leather being treated is to be subjected, has been reached; maintain the same for as long as experience determines is necessary,

and then release the pressure, remove the cover, and take out the then tempered leather.

As the tannages, age, and condition of leather differ widely, and also as the extent of tempering, pliability, etc. of the tempered leather differs widely for different uses, I find that pressure anywhere from twenty pounds to two hundred and I into the soles, thus greatly facilitating the entire modern methods and process of quick-shoemaking.

Another advantage of this forced penetration or permeation of the soles by the fluid resides in the fact that foreign matter which might be on the external surfaces of the soles is forced inwardly into the heart or center 01' the soles, and thus, when said soles are finished, as by bumng, a clean and even grain surface is provided; whereas soles tempered under prior methods, when buffed, frequently have streaks of discoloration due to the I "operation thereon, through the liquid supply effecting the pressure. This is an important advantage and obviates one of the serious diiiiculties heretofore experienced 'in the proposed tempering by building up air pressure through pneumatic v means, in which the same solution would quickly deteriorate through absorbing from successive batches of soles certain of the oils and greases in the leather being treated. Furthermore, the air pressure was always so elastic as to prevent uniformity of treatment, whereby by my present method, utilizing a direct hydraulic pressure, I secure a more positive forced penetration of the water into the leather, and by the continuous fresh supply of tempering solution maintain the liquid in the receptacle at all times in its best condition for successful uniform tempering of each succeeding batch or charge of leather.

Referring to the drawing illustrating in fragmentary form a part of the tempering apparatus of my said prior application Ser. No. 529,705,

The figure shows, for illustrative purposes, a suitable pressure tempering apparatus.

Referring to the drawing, I illustrates a metal receptacle shown in cross-section, and 2 designates a pressure-tight cover, which cover has reinforcing webs 3-3 and 4-4 in an upstanding column 5, adapted to be raised and lowered in vertical position by a pair of links 6 and I to maintain the cover in vertical alignment during the raising and lowering. A gasket I0 is positioned between the flange l2 on the receptacle I, and a corresponding flange I4 on the top 2. When the cover 2 is in place, movable clamps I5--I5 are swung into place, three or four of such clamps being utilized, either manually or automatically, and clamping pressure on each applied thereto, as by movement of the arm 20 of a bell crank lever pivoted at 2I and with its lower arm 22 pivotally secured at 23 to the lower portion I6 of each clamp I5 or in any other suitable manner.

Carried by the top 2 is an open framework indicated at 24, in which an open basket 25 is raised and lowered with the cover 2, and in which basket the soles or leather articles to be tempered may be carried.

Tempering liquid or solution is supplied from any suitable source of supply through a pipe or conduit 30 leading to a pump 3|, and thence by the pipe 32 through a valve 33 and a two-way valve 35, through a pipe 36, and opening into the receptacle I. From the two-way valve 35 is a relief pipe 31. In this particular form, as shown, in order to permit the pump 3| to operate continuously in building up pressure and to supply liquid to the receptacle I, a usual type of bypass 38 through a check valve 39 is provided. The twoway valve 35 has a handle 43 permitting the same to manipulate the valve, to shut off the supply through the pipe 32 at any desired time, and when the cover 2 is applied and clamped, then remove the handle 40 to permit the valve to continue the liquid supply through the pipe 32 and during the continued actuation of the pump 3|. The handle 40 is thus held in supplying position until the gauge 44 will indicate the pressure desired.

The cover 2 has a recess 45 to permit escape of air as the liquid rises in the receptacle I after the cover 2 is applied, thus driving out the air which may be entrapped within the receptacle when the cover is positioned and clamped. As the water rises it will also flow through the passage 45, lifting the fioat 50, which float is mounted on a stem 5| and carries, at its lowermost portion, a plate or washer 52 of suflicient dimensions to close the recess 45 and thus prevent the escape of fresh water, whereupon pressure is built up, as desired.

In operation, the cover being in raised position, the bundle or bundles of sole, leather are placed in the basket 25. Thereupon, the cover is lowered until the flange I4 rests on the gasket I0. Thereupon the clamps are swung into position, as shown; the bell crank lever is moved 'to apply a clamping pressure and to hold the cover 2 firmly onto the receptacle I, which receptacle is suitably supported to withstand this pressure. The handle 40 is moved to permit the pump 3| to force the tempering liquid through the pipe 32, reducing valve 33 and two-way valve 35 into the interior of the now pressure-tight receptacle I. As the liquid rises in the receptacle the air is forced out of the vent 45 until the rising water lifts the float 50 and closes the plate or'washer 52 against the opening of the vent 45. The valve 40 is then held until the gauge 44 shows the desired or predetermined pressure, whereupon it is moved to position, shutting off the supply from 32 and opening the receptacle through the pipe 36 and outlet31 to release the pressure and reduce the water level in the-receptacle I. Thereupon the clamps are released by movement of the bell crank lever 20.. They are swung outwardly and the cover 2 is raised, lifting the basket 25 with it. The tempering soles are removed and a fresh supply added, and the cycle repeated.

It will be appreciated that my method of tem-' pering leather, and particularly sole leather, consists in immersing the sole leather in the tempering liquid solution or fluid, within a pressuretight receptacle, and thereupon building up the pressure by the continued supply of additional tempering liquid.

This additional tempering liquid constantly affording a fresh supply not only gives a positive hydraulic pressure to the soles or leather being treated, but also, by the continued fresh supply with each successive batch to be treated, main tains the tempering liquid or solution, whether plain water or a specially treated solution, in proper condition for uniform tempering. I

While any pressure above barometric or atmospheric pressure of fifteen pounds per square inch can be'applied, I find that for ordinary purposes fifty to one hundred pounds per square inch or two or three minutes is ordinarily sufficient. On the other hand, an extremely low pressure, such as twenty pounds on certain leather, and if-maintained for a. substantial lapse of time, will give as beneficial a tempering effect as high pressures, viz. one hundred to two hundred pounds, for a second, the time and pres-i must ordinarily be more in temper and contain more moisture than for low-heeled men's shoes, for example, I find that commercially practicable pressures of from twenty pounds. to two-hundred and fli'ty pounds are desirable, even though fifty to one-hundred pounds pressure are usually sutficient for a large percentage of work.

Iclaim: 4 Y Y 1. The improved method of moistening leather soles preparatory to incorporating said soles into shoes during the processes of shoe manufacture, which consists in immersing said soles in a moistening liquid contained within a liquid-tight re- 3 ceptacle, and thereupon subjecting said iiouid to a hydraulic pressure for a desired length of time.

2. The improved method of moistening leather I which consists in immersing said soles in a moistening liquid contained within a liquid-tight receptacle, and thereupon subjecting said liquid to an increasing pressure by supplying further liquid into said receptacle until a predetermined pressure is attained.

WALLACE C. WRIGHT. 

